Why Choose the ABB RD3 Residual Current Relay?
The ABB RD3 is a modular Type A electronic residual current relay designed for earth leakage protection and residual current monitoring in industrial low-voltage electrical installations. As part of the ABB RD3 residual current relay series, it operates with an external ABB TR family toroidal transformer to detect residual current and provide a switching output for the associated protective device.
The RD3 offers extensive adjustment for protection coordination, with residual current sensitivity adjustable from 0.03–30 A and operating delay adjustable from 0–10 s. This enables the relay to be configured for different leakage-current thresholds and selective protection requirements, while Type A detection provides monitoring of alternating and pulsating DC residual currents.
Designed for DIN-rail mounting, the RD3 occupies 3 modules and operates from a 230–400 V AC supply at 50–60 Hz. It is designed for industrial installations and can be combined with ABB S200 miniature circuit breakers and compatible Tmax/XT moulded case circuit breakers, providing a flexible residual current protection solution for distribution boards and control panels.
Key Advantages
- Electronic residual current protection and earth leakage monitoring for industrial installations.
- 230–400 V AC operating voltage for direct integration into common low-voltage distribution systems.
- Wide 0.03–30 A adjustable sensitivity range.
- Adjustable 0–10 s operating delay supports selective protection coordination.
- Type A residual current detection for AC and pulsating DC residual currents.
- Designed for use with external ABB TR family toroidal transformers.
- Compact 3-module DIN-rail format simplifies installation in distribution boards.
- Compatible with ABB S200 miniature circuit breakers and suitable Tmax/XT moulded case circuit breakers for industrial protection systems.
Key Features
- ABB RD3 electronic residual current relay series.
- 230–400 V AC operating voltage.
- 50–60 Hz rated frequency.
- 0.03–30 A adjustable residual current sensitivity.
- 0–10 s adjustable tripping delay.
- Type A residual current detection.
- 8 A at 250 V AC output contact capacity.
- Maximum 3 Ω resistance between the toroidal transformer and relay.
- Remote reset connection length up to 15 m.
- IP20 protection rating.
- Maximum terminal conductor section of 2.5 mm².
- Compliant with IEC/EN 60947-2 Annex M.
Reliable Residual Current Protection for Industrial Installations
The ABB RD3 operates with an external toroidal transformer surrounding the active conductors of the monitored circuit. During normal operation the vector sum of the currents passing through the toroid is effectively zero. An insulation fault or leakage path to earth creates an imbalance, which is detected by the toroidal transformer and transmitted to the RD3 relay.
The relay compares the detected residual current with the selected operating threshold and delay. When the configured conditions are reached, its output can initiate the required protection or signalling action. The broad 0.03–30 A sensitivity and 0–10 s delay ranges make the RD3 suitable for coordinated earth leakage protection across a wide variety of industrial distribution systems.
Typical Applications
- Industrial residual current and earth leakage protection.
- Low-voltage switchboards and distribution panels.
- Industrial machinery and production equipment.
- Electrical systems using ABB S200 miniature circuit breakers.
- Installations using compatible ABB Tmax/XT moulded case circuit breakers.
- Control panels requiring adjustable earth fault monitoring.
